1. Field of the Invention
The present invention relates to electrical and optical equipment.
2. Description of the Related Art
Voice and data communications equipment is often designed such that printed circuit boards fitted with faceplates are inserted side-by-side into card cages. Connectorized assemblies (e.g., fiber optic jumper cables terminated at each end with a connector) are used to transmit (optical) signals from point to point within the card cage, e.g., from the circuit board to the faceplate, between two points within the same circuit board, between two different circuit boards, etc. Typically, four to eight fiber optic jumper cables may be used per circuit board in a cage. In some instances, an even greater number of jumper cables per circuit board may be required. Additional fiber optic jumper cables may also be needed for connections between different card cages, cabinets, or shelves.
Under current practice, two ends of a fiber optic jumper cable are connectorized and manually attached to the specified points, e.g., to the circuit board and faceplate. The amount of slack in the fiber between the points of attachment may vary depending on the distance between those points, length of the jumper cable, and other geometrical or topological constraints. In addition, jumper cables are often intentionally made longer than would be necessary to make the specified connections in order to have an extra length of fiber for repairs, such as replacement of broken connectors or removal of damaged sections of fiber. For these reasons, fiber optic jumper cables often end up dangling, jutting out, or otherwise protruding, e.g., from the surface of the circuit board.
During installation and/or maintenance, circuit boards are usually inserted into and/or pulled out of the card cage. An often occurring problem is that a dangling or protruding fiber optic jumper cable is damaged when it catches an obstacle, e.g., a piece of equipment within the cage, constriction of the card slot, or another jumper cable protruding from a different circuit board. Repair and replacement of the damaged fiber optic jumper cables may add significantly to the operational cost of telecommunication equipment.
In one embodiment, the present invention provides a jumper cable module for use with communication equipment. The module provides proper tensioning for jumper cables and retains them in a protected manner. The module includes a pulley and an eccentric cam pivotally connected to a base plate. A jumper cable is wrapped around grooves in the pulley and cam such that the connectorized ends of the cable extend out and attach to particular connection points (e.g., on the same or on two different circuit boards). The cam is turned about its axle to produce the desired tension of the cable. For maintaining the tension, the cam may incorporate a tensioning mechanism, e.g., a spring-loaded ball mechanism or a serrated edge ratchet. When the cable needs to be removed from the module, the tensioning mechanism is disengaged and the cam is turned to create slack in the cable for ease of cable removal. A module that includes stacks of pulleys and cams may handle multiple jumper cables. The present invention can be used to reduce damage to and improve handling of jumper cables during installation and maintenance of communication equipment.
According to one embodiment, the present invention is a jumper cable module, comprising: (a) a pulley connected to a base plate; and (b) a cam pivotally connected to said base plate, wherein: the jumper cable module is configured to provide tensioning to a jumper cable (i) placed within the jumper cable module and (ii) connected to connection points, which tensioning is achieved by rotating the cam to a selected angular position.
According to another embodiment, the present invention is a method of tensioning a jumper cable connected to connection points, the method comprising the steps of: (a) placing the jumper cable within a jumper module, wherein the jumper cable module comprises a pulley connected to a base plate and a cam pivotally connected to said base plate; and (b) rotating the cam to a selected angular position to achieve desired tension in the jumper cable.